Call of Duty: Ghosts' Extinction mode

The recently revealed Extinction mode for Call of Duty: Ghosts, which pits four soldiers against an alien infestation, will feature a class-based system for up to four players.

On the game's official blog, developer Infinity Ward explains how those classes are expected to work together.

Extinction mode's classes follow some fairly traditional roles. There's the Tank, which has 25 percent more health than other classes, allowing him or her to play more aggressively. By leveling up, Tank players can see their health boosts grow even further. On the offensive side is the Weapon Specialist, which deals 20 percent more damage than the norm.

The other two classes, Medic and Engineer, fill support roles. Medics can revive downed players more quickly, and gain faster movement and healing abilities as they level up. Engineers can provide armor assistance to the team's drill, which is used to destroy an alien hive, and help earn extra bonus cash.

For more gameplay details, watch the game's creators break down how Extinction will work and how it was conceived.

Players will be able to experiment with Extinction's classes and building their own teams when Call of Duty: Ghosts launches next week on PlayStation 3, Wii U, Windows PC and Xbox 360.